Orbitofacial neurofibromatosis: clinical characteristics and treatment outcome.

PURPOSE: To report clinical observations and surgical management in a large series of patients with orbitofacial neurofibromatosis type 1 (OFNF). PATIENTS AND METHODS: Patients were identified and medical records reviewed for demographic data, ophthalmologic examinations, surgical interventions, and procedure outcome to create a retrospective, non-comparative case series of patients with OFNF seen at one medical centre over a 23-year period. RESULTS: Sixty patients with OFNF (31 females and 29 males; mean age, 14 years) were followed for an average of 5.7 years. Presenting signs and symptoms included eyelid swelling in all patients, ptosis in 56 (93.3%), proptosis in 34 (56.6%), dystopia or strabismus in 30 (50%), and decreased visual acuity in 50 (83.3%). Surgical intervention included ptosis repair in 54 (90%; mean 1.6 surgical procedures), facial and orbital tumour debulking in 54 (90%; mean 2.3 surgeries), and canthoplasty in 28 (46.6%) patients. Eleven patients required enucleation or exenteration of a blind eye. CONCLUSION: Patients with OFNF often require multiple procedures to preserve vision, prevent additional disfigurement, and achieve cosmetic rehabilitation. Patients need regular ophthalmological monitoring given the potential for progressive visual and cosmetic consequences.

Inpatient preseptal cellulitis: experience from a tertiary eye care centre.

OBJECTIVE: To describe causes of preseptal cellulitis (PSC) and outcome of treatment in patients admitted to a tertiary eye-care centre. METHODS: A 15-year (January 1991 to December 2005) review of inpatients with clinical signs and symptoms or radiological evidence suggestive of PSC was conducted. Patients with infection anterior to the orbital septum which is characterised by acute onset of eyelid oedema, tenderness, erythema, warmth and chemosis were included in the study. RESULTS: Among the 104 patients (male:female 64:40) fulfilling the diagnostic criteria for PSC, acute dacryocystitis (ADC) was the most common predisposing cause in 32.6% patients, followed by sinusitis/upper-respiratory infection (URI) in 28.8% and trauma/recent surgery in 27.8% patients. Fifty-per cent required surgical intervention including dacryocystorhinostomy/probing/stenting in 74% and abscess/chalazian drainage in 28.8%. In 38.5% of the patients who had surgical intervention, microbiological investigations were carried out, cultures were positive in 90%. Most common micro-organisms recovered included Staphylococcus and Streptococcus species followed by Haemophilus influenzae and Klebsiella pneumonia. Blood cultures were positive in two of the 34 patients in whom blood was drawn. Most patients responded to systemic antibiotics with resolution of PSC. Seven patients developed late complications which included subacute lid abscesses, eyelid necrosis and cicatricial ectropion. CONCLUSIONS: Sinusitis/URI, ADC and recent history of trauma/surgery were the most common cause of PSC in admitted patients. Although most patients responded to systemic antibiotics, surgical intervention was necessary in some patients to prevent associated complications.

Development of early choroidal neovascular membrane in a young myope after LASIK.

PURPOSE: To describe development of early choroidal neovascular membrane (CNVM) after laser-assisted in situ keratomileusis (LASIK) procedure in a young myopic patient that was successfully managed by photodynamic therapy (PDT). METHODS: A retrospective interventional case report. RESULTS: A 20-year-old woman with myopic astigmatism underwent uneventful LASIK surgery resulting in best-corrected visual acuity (BCVA) of 20/20 bilaterally. One week later, the patient presented with decreased VA in the right eye and was found to have clinical evidence of central serous chorioretinopathy (CSC). She was treated with systemic corticosteroids without any improvement. Two weeks after LASIK, the patient's VA was 20/200 and clinical evidence of early CNVM was confirmed by fluorescein angiography, indocyanine green angiography, and optical coherence tomography (OCT). PDT resulted in the regression of her CNVM with improvement in her VA and OCT findings. CONCLUSIONS: Systemic corticosteroids may enhance CNVM in patients with LASIK-induced early CNVM. PDT may be effective in the resolution of LASIK-induced CNVM.

Orbital cellulitis following implantation of aqueous drainage devices.

PURPOSE: Orbital cellulitis (OC) as a complication of implanted aqueous drainage devices (ADD) for glaucoma is an uncommon phenomenon. The authors report two cases of infectious OC in patients with a history of congenital glaucoma and placement of ADD. METHODS: Clinical records of two patients with ADD who subsequently developed OC were reviewed for presenting symptoms, signs, medical and surgical management, and final outcome. RESULTS: In the first case, an 11-year-old girl was found to have evidence of OC 9 days after the implantation of a Krupin-Denver valve. In the second case, a 14-month-old girl presented with similar findings 8 months following the implantation of an Ahmed valve. In both cases, ultrasonography demonstrated evidence of orbital inflammation and in one patient computed tomography scan was consistent with OC. In both cases, prompt institution of systemic antibiotics resulted in resolution of the clinical signs. In the first case, diagnosis was made early and the patient was promptly treated with systemic antibiotics, resulting in resolution of her symptoms without the need for implant removal. Because of the delayed presentation in the second case, an infected implant had to be removed to achieve resolution in addition to aggressive with antibiotics treatment. CONCLUSIONS: Although rare, infectious OC may occur following implantation of ADD. Early recognition and intervention may be required to achieve resolution of the infection.

Progressive severe visual loss after long-term withdrawal from thioridazine treatment.

PURPOSE: To report advanced thioridazine-induced retinopathy in a 50-year-old woman with evidence of progressive severe loss of vision over 30 years after withdrawal from thioridazine treatment. METHODS: The ocular fundus examination revealed areas of retinal pigment epithelium (RPE) clumping as well as generalized atrophy of the RPE and choroid. The patient experienced visual loss to the level of no light perception in both eyes despite the fact that the funduscopic appearances of her optic nerves and retinal vasculature remained relatively normal. CONCLUSIONS: This case demonstrates that severe progressive visual loss can occur several years after the cessation of chronic thioridazine treatment.

Optic nerve avulsion from door-handle trauma in children.

AIM: To report severe visual loss caused by optic nerve avulsion (ONA) in children with door-handle trauma. METHODS: Clinical records at a tertiary eye care hospital, of 14 children who sustained severe visual loss as a result of door-handle injuries, were reviewed. The data were analysed for location, presenting symptoms and signs, diagnostic studies, intervention, and the cause of visual loss. RESULTS: There were 11 males and three females with an average age of 8 years and an average height of 125 cm. The place of trauma was home in 11 and school in three children. Presenting visual acuity (VA) was light perception (LP) in five patients and no light perception (NLP) in nine. All the 14 children had evidence of ONA and four patients had ruptured eye globes that required initial repair. The diagnosis of ONA was made clinically or by imaging studies and confirmed histopathologically in eyes that were enucleated. Average follow up was 28.8 months (range 4 months to 8 years). Final VA was LP in one patient and NLP in 13 patients, eight eyes required enucleation for painful blind eye or to achieve optimal cosmesis. CONCLUSION: ONA was the common cause of visual loss in children who sustained ocular trauma caused by door-handles.

Inhibition of RPE lysosomal and antioxidant activity by the age pigment lipofuscin.

PURPOSE: To determine whether lipofuscin is detrimental to lysosomal and antioxidant function in cultured human retinal pigment epithelial (RPE) cells. METHODS: Isolated lipofuscin granules were fed to confluent RPE cultures and the cells maintained in basal medium for 7 days. Parallel cultures were established that did not receive lipofuscin. Cultures were either exposed to visible light (390-550 nm) at an irradiance of 2.8 mW/cm(2) or maintained in the dark at 37 degrees C for up to 24 hours. Cells were subsequently assessed for cell viability, lysosomal enzyme activity, and antioxidant capacity. RESULTS: There was no loss of cell viability during the first 3 hours of light exposure, whereas a 10% loss of viability was observed in lipofuscin-fed cultures after 6 hours' exposure to light. Activities of acid phosphatase, N-acetyl-beta-glucuronidase, and cathepsin D were decreased by up to 50% in lipofuscin-fed cells exposed to light compared with either unfed cells or cells maintained in the dark. There was also a decrease in the antioxidant potential of RPE cells. Catalase and superoxide dismutase activities decreased by up to 60% and glutathione levels by 28% in light-exposed lipofuscin-fed cells compared with unfed cells or cells maintained in the dark. CONCLUSIONS: Lipofuscin has the capacity to reduce the efficacy of the lysosomal and antioxidant systems in RPE cells that may play an important role in retinal ageing and the development of age-related macular degeneration.

Photocytotoxicity of lipofuscin in human retinal pigment epithelial cells.

Lipofuscin accumulates with age in a variety of highly metabolically active cells, including the retinal pigment epithelium (RPE) of the eye, where its photoreactivity has the potential for cellular damage. The aim of this study was to assess the phototoxic potential of lipofuscin in the retina. RPE cell cultures were fed isolated lipofuscin granules and maintained in basal medium for 7 d. Control cells lacking granules were cultured in an identical manner. Cultures were either maintained in the dark or exposed to visible light (2.8 mWcm2) at 37 degrees C for up to 48 h. Cells were subsequently assessed for alterations in cell morphology, cell viability, lysosomal stability, lipid peroxidation, and protein oxidation. Exposure of lipofuscin-fed cells to short wavelength visible light (390-550 nm) caused lipid peroxidation (increased levels of malondialdehyde and 4-hydroxy-nonenal), protein oxidation (protein carbonyl formation), loss of lysosomal integrity, cytoplasmic vacuolation, and membrane blebbing culminating in cell death. This effect was wavelength-dependent because light exposure at 550 to 800 nm had no adverse effect on lipofuscin-loaded cells. These results confirm the photoxicity of lipofuscin in a cellular system and implicate it in cell dysfunction such as occurs in ageing and retinal diseases.

Maillard reactions in lens proteins: methylglyoxal-mediated modifications in the rat lens.

The nonenzymatic Maillard reaction is thought to contribute to aging and cataract formation in the lens. As levels of methylglyoxal (MG) and glutathione (GSH) affect the reaction, we examined the relationship of these factors and determined the effect of a glyoxalase I inhibitor on the Maillard reaction. Rat lens cultures were maintained for up to 3 days in TC-199 medium with or without 20 m m glyceraldehyde (GLD) and 250 microm S-[N-hydroxy-N-(4-chlorophenyl) carbamoyl] glutathione diethyl ester (HCCG diester). We measured GSH, MG, D-lactate, glyoxalase I activity, immunoreactive MG-derived advanced glycation endproducts (MG-AGEs) and imidazolysine in organ cultured rat lenses. In vitro experiments with isolated rat lens proteins revealed that HCCG alone inhibited glyoxalase I activity in a dose-dependent manner. In organ cultured rat lens protein, GLD increased MG levels 24-fold, and the addition of HCCG diester further increased it by about two-fold. GSH levels fell sharply in the presence of GLD and this was prevented to some extent by the presence of HCCG diester. D-lactate production in the lens was suppressed by HCCG diester treatment. Dialysed lens proteins retained glyoxalase I activity, indicating that the enzyme was unaltered during incubation. MG-AGEs and imidazolysine levels were significantly higher (P<0.05) in GLD-treated lenses, but a combination of HCCG diester and GLD lowered immunoreactive MG-AGEs and imidazolysine levels compared to GLD alone. HCCG had no significant effect on MG-AGE formation in lens proteins incubated with GLD or MG. We conclude that exogenous GLD enhances MG and MG-AGE levels in the rat lens and that this increase is accompanied by a loss in GSH. In addition, inhibition of glyoxalase I promotes MG accumulation.

Immunochemical detection of dicarbonyl-derived imidazolium protein crosslinks in human lenses.

PURPOSE: To determine the formation of imidazolysine, a Maillard reaction derived protein crosslink in the human lens in relation to aging and cataract by immunochemical methods. METHODS: Antibodies against RNase-imidazolysine were raised in rabbits. The antibodies were tested for their specificity for imidazolysine by using various imidazolysine-like compounds and imidazoles. A competitive ELISA tested human lens water-soluble proteins and enzyme-digested water-insoluble proteins for immunoreactivity against the antibodies. RESULTS: The antibodies strongly reacted with structurally related imidazolysine and GOLD (glyoxal-lysine dimer) and thus precluded us from distinguishing imidazolysine from GOLD in the human lens. We assumed that the detected immunoreactivity is due to a combination of GOLD and imidazolysine. The antibodies did not react with histidine. The immunoreactivity in lens proteins was expressed as units of imidazolium crosslinks per unit of protein (1 unit = 1% inhibition of antibody binding to microplate well, 1 unit of protein = approximately 0.3 mg protein). The levels in the water-insoluble proteins were 8.4 +/- 4.5 units (mean +/- SD) and 40.4 +/- 8.5 units per unit of protein in young and old lenses, respectively. Cataractous lenses showed significantly higher levels (58.8 +/- 8.1 units, P < 0.05) when compared to age-matched normal lenses and highest levels were observed in brunescent cataractous lenses (76.6 +/- 13.4 units). The levels were negligible in the water-soluble proteins of young lenses and were 5 to 14-fold lower when compared to the water-insoluble proteins from the same lenses. Western blot analysis of lens proteins showed that the antigens are primarily present in the high molecular weight protein aggregates. CONCLUSIONS: This study provides additional evidence for alpha-dicarbonyl-mediated protein crosslinking in the human lens and suggests that such reactions could play a role in lens aging and cataractogenesis.

Immunochemical detection of oxalate monoalkylamide, an ascorbate-derived Maillard reaction product in the human lens.

Carbohydrates with reactive aldehyde and ketone groups can undergo Maillard reactions with proteins to form advanced glycation end products. Oxalate monoalkylamide was identified as one of the advanced glycation end products formed from the Maillard reaction of ascorbate with proteins. In these experiments, we have analyzed human lens proteins immunochemically for the presence of oxalate monoalkylamide. Oxalate monoalkylamide was absent in most of the very young lenses but was present in old and cataractous lenses. The highest levels were found in senile brunescent lenses. Incubation experiments using bovine lens proteins revealed that oxalate monoalkylamide could form from the ascorbate degradation products, 2,3-diketogulonate and L-threose. These data provide the first evidence for oxalate monoalkylamide in vivo and suggest that ascorbate degradation and its binding to proteins are enhanced during lens aging and cataract formation.

Methylglyoxal-derived modifications in lens aging and cataract formation.

PURPOSE: To determine whether the Maillard reaction of methylglyoxal is associated with human lens aging and cataractogenesis and to investigate how glutathione depletion affects methylglyoxal-derived modifications in organ-cultured lenses. METHODS: Antibodies against methylglyoxal-derived modifications were developed in rabbits and purified by immunoaffinity chromatography. A competitive enzyme-linked immunosorbent assay (ELISA) measured methylglyoxal-derived products in human lens proteins. Lenses of galactosemic rats grown in organ culture were used to assess the role of glutathione-dependent pathways in methylglyoxal metabolism and Maillard reactions. RESULTS: Methylglyoxal-derived modifications in the human lens were age dependent, and brunescent lenses had the highest levels of these modifications. Immunofluorescence staining identified antigens distributed throughout the lens, with higher levels in old lenses than in younger ones. Experiments with normal or galactosemic rat lenses grown in organ culture showed that lens proteins do not have an increase in methylglyoxal-modified proteins when cultured in medium containing 500 microM methylglyoxal alone, but they accumulate modified proteins when cultured with DL-glyceraldehyde. Inclusion of 30 mM glucose in the medium marginally increased methylglyoxal-derived products, but there was no correlation between lens glutathione content and methylglyoxal-derived modifications. CONCLUSIONS: Methylglyoxal-mediated Maillard reactions that occur in the human lens may play a role in lens aging and cataract formation. Methylglyoxal is probably derived from metabolic pathways within the lens. Decreased glutathione in organ-cultured rat lenses does not significantly influence methylglyoxal-mediated Maillard reactions.

Immunological evidence for methylglyoxal-derived modifications in vivo. Determination of antigenic epitopes.

The Maillard reaction, a non-enzymatic reaction of ketones and aldehydes with amino groups of proteins, contributes to the aging of proteins and to complications associated with diabetes. Methylglyoxal (MG) is a 2-oxoaldehyde derived from glycolytic intermediates and produced during the Maillard reaction. We reported previously the formation of a lysine-lysine protein cross-linking structure (imidazolysine) and a fluorescent arginine modification (argpyrimidine) from the Maillard reaction of MG. Here we show that rabbit antibodies to MG-modified ribonuclease A identify proteins modified by the Maillard reaction of glucose, fructose, ribose, glyceraldehyde, glyoxal, ascorbate, and ascorbate oxidation products (dehydroascorbate, 2,3-diketogulonate, L-xylosone, and L-threose) in addition to those modified by MG. The antibody recognized imidazolysine and argpyrimidine and a glyoxal-derived lysine-lysine cross-link. It did not react with Nepsilon-carboxymethyllysine. Incubations with amino acids revealed strongest reactivity with Nalpha-t-butoxycarbonylarginine and MG, and we identified argpyrimidine as one of the epitopes from this incubation mixture. Serum proteins from human diabetics reacted more strongly with the antibody than those from normal individuals, and the levels correlated with glycemic control. Collagen from human corneas contained MG-derived modifications, with those from older subjects containing higher levels of modified proteins than those from younger ones. An immunoaffinity-purified antibody showed higher reactivity with old corneas than with younger ones and localized the antigens primarily within the stromal region of the cornea. These results confirm reported MG-derived modifications in tissue proteins and show that dicarbonyl-mediated protein modification occurs during Maillard reactions in vivo.

DNA breakage by uric acid and Cu(II): binding of uric acid to DNA and biological activity of the reaction.

Uric acid is present in human plasma in relatively high concentrations and is considered to be a natural physiological antioxidant. We have earlier shown that in the presence of Cu(II) and molecular oxygen, uric acid causes strand breakage in DNA. In this article, we show that uric acid fluorescence is quenched by addition of DNA, indicating the formation of uric acid-DNA complex. Uric acid-Cu(II)-mediated DNA strand scission is capable of bacteriophage inactivation and such inactivation is mediated through reduction of Cu(II) to Cu(I) and the generation of oxygen-derived radicals. It is indicated that the DNA breakage is repaired in E. coli and involves the repair of DNA polymerase.

Photoinduction of strand scission in DNA by uric acid and Cu(II)

Uric acid (2,6,8-trioxo purine) is produced in mammalian systems as an end product of purine metabolism and has been proposed as a natural, physiological antioxidant. In the presence of Cu(II) and molecular oxygen, uric acid caused breakage of calf thymus DNA and supercoiled plasmid DNA. Such breakage was considerably enhanced in the presence of visible light. The DNA cleavage did not appear to have any preferred site(s) or sequence(s) for strand scission. Uric acid catalyzed the reduction of Cu(II) to Cu(I), which was shown to be an essential intermediate in the DNA cleavage reaction. Uric acid also reduced oxygen to superoxide, and hydroxyl radicals were formed in the presence of Cu(II). The involvement of active oxygen species in the reaction was established by the inhibition of DNA breakage by known scavengers of oxygen radicals.

Mutagenicity of furfural in plasmid DNA.

Furfural is recognized as a dietary mutagen and is present in various foods and beverages. We have examined the mutagenic effect of furfural induced lesions in plasmid pBluescript SK(+/-). There was a progressive decrease in the transformation capacity of the plasmid as a function of furfural concentration with a concomitant increase in the number of mutant plasmids. Several mutant plasmids with reduced transformation capacity and a molecular size similar to the parental plasmid were isolated. A stretch of DNA of 108 basepairs within the multiple cloning region was sequenced. It was observed that the number of mutagenic events in the case of furfural damaged plasmid was not significantly greater than in spontaneously arisen mutants. These results were interpreted to indicate that furfural mediated DNA damage is efficiently repaired.